Control unit and switch used therein



y 1951 G. M. BEARDOW 2,993,963

CONTROL UNIT AND SWITCH USED THEREIN Filed Oct. 13, 1959 2 Sheets-Sheet 1 INVENTOR. eor ge M. Bea/ d 0w QTTURNEYS July 25, 1961 ow 2,993,963

CONTROL UNIT AND SWITCH USED THEREIN Filed Oct. l3, 1959 2 Sheets-Sheet 2 INVENTOR. Geo/ye M. Bea/dou TTORNEYS United States Patent CONTROL UNIT AND SWITCH USED THEREIN George M. Beardow, Redding Ridge, Conn., assignor of one-fourth to Nowell S. Beardow, Weston, Conn. Filed Oct. 13, 1959, Ser. No. 846,134 9 Claims. (Cl. 20030) The present invention relates to a control device of the type used in sampling or sequencing circuits or operations and to a switch unit used therein.

Heretofore in devices used in sampling or sequencing circuits involving very low voltages such as derived from thermocouples, photocells, strain-gauges, etc. for use in supplying the information to circuits making up telemetering systems, computers and monitoring systems a problem has arisen due to the fact that it has been difficult to accurately operate such devices because of the electrical noise level encountered in the operation of the switch units therein.

It is an object of the present invention to provide a control unit in which one or more circuits may be sampled or sequenced and in which the circuit is closed and freed from the actuator so that the electrical noise does not form an objectionable part of the signal.

A further object of the invention resides in a switch unit for use in the control unit wherein the contacts are normally urged into closed circuit position but are held in open circuit position by a tensioned operator which, when actuated, moves the contacts to closed circuit position and thereafter relieves the operator from engagement with the movable contact whereby the contacts are free of any vibration and the transmission of any electrical noise from the operator.

A feature of the invention resides in a simple switch construction which insures good contact between the contacts in closed circuit position and which maintains the contacts closed against any vibration or chattering, all for the purpose of better controlling the circuit to which they are connected.

Other features and advantages of the invention will be apparent from the specification and claims when considered in connection with the accompanying drawings in which:

FIGURE 1 shows the control unit partly in section.

FIG. 2 .shows a sectional view on the line 2-2 of FIG. 1. V

FIG. 3 shows a switch unit with the cover plate partly removed showing the relation of the contacts in open circuit position.

FIG. 4 is a view similar to FIG. 3 showing the contacts at the pointat which the circuit is closed.

FIG. 5 is a view similar to FIG. 3 showing the switch in operated position.

FIG. 6 is a sectional view taken along line 66 of FIG. 3.

As shown herein, the control unit 10 is adapted to have a plurality of switch units 1 1 mounted therein to be operated in sequence for sampling, actuating or otherwise controlling a plurality of circuits. While the switch units may be arranged in any arrangement which will permit them to be operated by a relatively movable cam or the like in a sequence or predetermined pattern, for the purpose of illustrating the invention they are shown in conjunction with a rotary unit which comprises a frame 12 having a base 13 by which it may be mounted. The frame has a bore 14 extending therethrough and a shaft 15 rotatably mounted in the bore. A motor or other suitable drive means 16 is connected to rotate the shaft. An annular channel 17 is provided on the frame intermediate the ends thereof and is adapted to have mounted therein a plurality of spaced switch units 11. In the illustrated form of the invention the switch units are mounted "ice in a groove 18 disposed in the bottom of the channel and are provided with lateral projections 19 at the upper edge thereof which are adapted to fit in recesses 20 in the bottom of the channel adjacent the groove for properly locating the switches therein. The switches are held in place by means of clamp members or hands 21 which overlie the lateral projections and clamp them against the shoulders 22 formed by the bottom of the recesses.

The bottom of the groove is provided with a plurality of apertures 23 through which an actuator 24 for the switch means projects and a rotary cam means 25 is secured to the shaft to engage the actuators to operate the switches as will be explained. As shown in FIG. 2, the rotary cam means 25 is provided with a projection 26 having oppositely directed cam surfaces 27 thereon which engage the bottom of the actuator with a wiping action in either direction of rotation for moving it inwardly to close the switch.

It will be seen, therefore, that by the proper projection of the actuator and the location of the lateral projections 19 on the switch which are supported by the shoulders 22 on the recesses, the switches can be accurately held in proper position on the device by the clamp member held in place by bolts 28 and yet can be readily removed and replaced when desired.

The switches may be connected together to provide for a longer sampling period or can be individually connected to a connector or plug 29 carried in an end plate 30 secured to the frame by bolts 31. The device or devices which are to be tested, sampled or sequentially operated can be connected to the plug by the usual jumpers, not shown.

:If desired a closure 32 can be provided to overlie the channel in the frame and can be supported by shoulders 33, 34 adjacent the channel as shown in FIG. 1 to protect the switch units.

The switch units 11 of the present invention, as shown in FIGS. 3 to 5, comprise a housing 40 molded or otherwise formed of insulating material. The housing has a pair of laterally projecting portions 19 at the upper edge which are received in the cooperating recesses 20 on the frame. The lower surfaces 19a of the projections are accurately formed so as to be supported on the shoulder 22 to accurately locate the unit on the frame. The housing above these locating portions is split at 41 to provide the desired resiliency in holding the unit in position by the clamping rings.

As shown in the drawings, the housing has a recess 42 formed therein and into which one end of a stationary contact 43 projects and is provided with a contact portion 44. The other end of the stationary contact is secured in the housing and has a terminal 45 projecting from the upper face 40a of the housing. Cooperating with the stationary contact is a movable contact member 46 of resilient material carried by the housing and connected to a terminal 47 projecting from the face 40a. One end 46a of the movable contact, which is of resilient material, extends into the recess to lie adjacent the contact 43 and is normally urged by the resiliency of the material into closed circuit position with the contact portion 44. Preferably the resiliency of the contact material is augmented, in the illustrated form of the invention, by a spring 48 having one end fixed to the housing and the other end secured to the movable contact.

The operator for the contact comprises a resilient operating member 49 having one end 50 embedded in or secured to the housing and the other end 51 extending into the recess in a position to lie below the movable contact and to be located on a side thereof opposite to the stationary contact. The operator has a contact-engaging portion 53 disposed in the recess and adapted to overlie the movable contact. While this contact-engaging portion can be formed by bending the operating member, it is herein shown as a separate member secured to and projecting above the operating member and engaging and overlying the end of the movable contact member as shown in FIGS. 3 to 5. The operator is normally urged to the position shown in FIG. 3 wherein the contactengaging portion 53 engages the end of the movable contact and holds it, against the urging means, in an open circuit position.

The actuator for the switch comprises a plunger 54 having a grooved head 55 engaging the operator for the switch, which plunger is slidable in a tubular bearing 56. Preferably, the bearing is made of brass or other similar material and the plunger is made of an insulating material such as Bakelite polyethylene, or vinyl compounds or the like material. It will be noted that the plunger in normal position extends a predetermined distance below the end of the metallic tube and in position to be engaged by the cam means on the shaft. As the shaft rotates and cam surfaces 27 pass under and engage the actuator it moves upwardly and the switch parts assume the position shown in FIG. 4 wherein the movable contact engages the stationary contact portion 44. Inasmuch as the movable contact is urged toward the stationary contact, it will be held and controlled in its movement by the projection 53 until it makes good electrical engagement with the contact portion 44 after which the urging means holds it in firm circuit closing position. As the plunger continues to move the operator upwardly to the operated position of FIG. 5, it will be noted that the portion 53 of the operator is completely free of the movablecontact and any noise or vibration which might be set up by the actuator is prevented from being transmitted to the movable contacts so that extremely low voltages can be handled by the contacts during the sampling or other operations without interference by the electrical noise factor or other vibration on the switch.

With this arrangement it will be seen that the movable contact member will be pressed at all times against either the member 53 or the contact portion 44 so that undesirable vibrations cannot be set up in the movable contact member as might produce objectionable electrical noise or chatter.

As shown in the drawings, a transparent cover 57 may be provided to close the recess 42. This cover .can be mounted on a shoulder 58 surrounding the recess so as to be flush with the outer surface of the housing. The cover seal out foreign material from contaminating the contacts and still permits an inspection of the operation of the switch unit.

Also provided is an adjusting screw 59 threaded in the housing in position to engage the stationary contact for altering the position thereof, and more specifically, to alter the point at which the portion 44 is engaged by the movable contact, thus varying the time interval of the contact closure during the operation of the switch unit.

From the foregoing it will be seen that the control unit of the present invention permits a sampling, sequencing or actuation of a plurality of circuits, particularly circuits having low voltage therein, in which the switch units are of such a construction that the circuits can be closed without having interference imposed on the signals carried therein and the electrical noise or vibrations usually set up by the actuators for the switches.

The novel switch unit according to the present invention has a contact arrangement wherein a movable contact is held against an operating member while held in open circuit position and when moved in closed circuit position at first engages the stationary member and ceases to be engaged with the operating member so that electrical contact is made in circuit closed position which is free of vibrations.

A further advantage of the switch of the present invention resides in the fact that it is of simple construction and is easily operated, all without electrical noise and 4 vibration being present as heretofore encountered in devices of this type.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

I claim:

1. A control unit comprising a frame; means detachably mounting a plurality of electrical switch units on the frame, each electrical switch unit comprising a housing having a stationary contract member and a cooperable movable contact member for closing a circuit therebetween, urging means urging the movable contact member to closed circuit position, an operating member mounted on the housing independently of said movable contact member and having a contact-engaging portion overlying the movable contact member to form the sole operating connection thereto, said operating member being urged to a normal position wherein the contactengaging portion engages and holds the movable contact in open circuit position, and an actuator means cooperating with the operating member; and cam means movable relative to the actuator means for moving said actuator means and operating member from normal position and for moving the contact-engaging portion and the movable contact in engagement therewith toward said stationary contact, the movable contact member moving into electrical engagement with the stationary switch member prior to completion of movement of the operator which moves the contact-engaging portion out of engagement with the movable contact member whereby the closed contacts are free of any connection to the operating member, thus eliminating electrical noise or vibration as may be transmitted thereto by the actuator and cam means.

2. A control unit comprising a frame; means detachably mounting a plurality of electrical switch units in sideby-side relation on the frame, each electrical switch unit comprising a housing having a stationary contact member mounted on the housing, a movable contact member mounted on the housing and having a portion cooperable with the stationary contact to close a circuit therebetween, urging means urging the movable contact to closed circuit position, a resilient operating member mounted on the housing independently of said movable contact member and having a contact-engaging portion overlying the movable contact member to form the sole operating connection thereto, said resilient member having a normal position wherein the contact-engaging portion engages and holds the movable contact in open circuit position, and an actuator means cooperating with theoperating member; and cam means movable relative to the actuator means for moving said actuator means and operating member from normal position and for moving the contact-engaging portion and the movable contact in engagement therewith toward said stationary contact, the movable contact member moving into electrical engagement with the stationary switch member prior to completion of movement of the actuator which moves the contact-engaging portion out of engagement with the movable contact member whereby the closed contacts are free of any connection to the operating member, thus eliminating vibration as may be transmitted by the actuator and cam means.

'3. A control unit comprising a frame having an annular channel therein, a central bore concentric with said channel and a plurality of apertures in the bottom of the channel communicating with the bore; means including spaced recesses adjacent the channel for detachably mounting a plurality of electrical switch units in side by-side relation on the frame, each electrical switch unit comprising a housing having a stationary contact member mounted on the housing, a movable contact member mounted on the housing and having a portion cooperable with the stationary contact to close a circuit therebetween, urging means urging the movable contact to closed circuit position, a resilient operating member mounted on the housing and having a contact-engaging portion overlying the movable contact member, said resilient member having a normal position wherein the contact-engaging portion engages and holds the movable contact in open circuit position, and an actuator means cooperating with the operating member and projecting fromthe housing and through one of the aperatures in the bottom of the channel; and a rotatable shaft disposed in the bore and having cam means thereon movable relative to the actuator means for moving said actuator means and operating member from normal position and for moving the contact-engaging portion and the mova- -ble contact in engagement therewith toward said stationary contact, the movable contact member moving into electrical engagement with the stationary switch member prior to completion of movement of the actuator which moves the contact-engaging portion out of engagement with the movable contact member whereby the closed contacts are free of any vibration as may be transmitted by the actuator and cam means. p

4. Acontrol unit comprising a frame having an an nular channel therein provided with a removable closure, a central bore concentric withsaid channel and a plurality of apertures in the bottom of the channel communicating with the bore; means including spaced recesses adjacent the channel for detachably mounting a plurality of electrical switch units in side-by-side relation on the frame, each electrical switch unit comprising a housing havinga locating projection seated in said recesses and a stationarycontact member mounted on the housing, a movable contact member mounted on the housing and having a portion cooperable with the stationary contact to close a circuit therebetween, terminals connected to said contact members and being exposed at the top of the housing, urging means urging the movable contact to closed circuit position, a resilient operating member mounted on the housing and having a contact-engaging portion overlying the movable contact member, said resilient member having a normal position wherein the contact-engaging portion engages and holds the movable contact in open circuit position, and an actuator means cooperating with the operating member and projecting from the housing and through one of the apertures in the bottom of the channel; a rotatable shaft disposed in the bore and having cam means thereon movable relative to the actuator means for moving said actuator means and operating member from normal position and for moving the contact-engaging portion and the movable contact in engagement therewith toward said stationary contact, the movable contact member moving into electrical engagement with the stationary switch member prior to completion of movement of the actuator which moves the contact-engaging portion out of engagement with the movable contact member whereby the closed contacts are free of any vibration as may be transmitted by the actuator and cam means; a connector mounted on the frame; and means connecting said terminals to said connector.

5. An electrical switch unit comprising an insulated housing having a stationary contact member and a movable contact member mounted thereon, urging means urging the movable contact member into closed circuit position, an operating member mounted on the housing separate from the movable contact member and having a contact-engaging portion overlying a part of the movable contact member to form the sole operating connection thereto and normally holding the movable contact in open circuit position against the action of the urging means, and an actuator means carried by the housing and cooperating with the operating member for moving said operating member from said normal position toward an operated position, the movable contact member being pressed against said contact-engaging portion of the operating member until said contact member is in electrical engagement with the stationary contact member and held in closed circuit position by the urging means, said engagement being prior to completion of movement of the operating member to operated position in which the contact-engaging portion is out of engagement with the movable contact member and the contacts are free of the operating member whereby the closed contacts are maintained closed and free of any vibration as may be transmitted by the actuator.

6. An electrical switch unit comprising a housing, a stationary contact member mounted on the housing, a movable contact means mounted on the housing and having a portion thereof cooperable with the stationary contact to close a circuit therebetween, urging means urging the movable contact means to closed circuit position, a resilient operating member mounted on the housing independently of said movable contact means and having a contact-engaging portion overlying a part of the movable contact means to form the sole operating connection thereto, said resilient operating member having a normal position wherein the contact-engaging portion engages and holds the movable contact means in open circuit position, and an actuator means cooperating with the operating member for moving said operating member from said normal position toward said stationary contact member to an operated position, the movement of the movable contact means toward said stationary contact member under the urging means being controlled by the engagement therewith of the contact-engaging portion of the operating member, the movable contact means engaging and being held in electrical engagement with the stationary contact member by the resilient means prior to completion of movement of the operating member to operated position in which the contact-engaging portion is out of engagement with the movable contact means whereby the closed contacts are maintained closed and free of any connection to the operating member, thus eliminating vibration as may be transmitted by the actuator.

7. An electrical switch unit comprising a housing of insulating material having a stationary contact mounted therein; a movable contact means mounted on the housing and having a portion cooperable with the stationary contact to close a circuit therebetween; urging means urging the movable contact means to closed circuit position; an operating member mounted on the housing independently of the movable contact means and having a contact-engaging portion overlying the movable contact means, said operating member being urged to a normal position wherein the contact-engaging portion engages and holds the movable contact means away from the stationary contact and in open circuit position, and means cooperating with the operating member for moving said operating member from normal position to an operated position, the contact-engaging portion permitting and controlling the movement of the movable contact means into engagement with said stationary contact and permitting said movable contact means to be held in electrical engagement with the stationary contact member by the urging means prior to completion of movement of the operating member to operated position whereby the closed contacts are free of any operating connection with the operating member and of any vibration as may be transmitted thereto by the operating member.

8. An electrical switch unit comprising a housing having a recess therein; a stationary contact member mounted on the housing having one end projecting into the recess; a movable contact member mounted on the housing and having a portion thereof cooperable with the stationary contact to close a circuit therebetween; urging means urging the movable contact to closed circuit position; a separate operating member mounted on the housing and disposed on the side of the movable contact opposite said stationary contact and having a contact-engaging portion overlying the movable contact member to form the sole operating connection thereto, said operating member being urged away from the stationary contact having a normal position wherein the contact-engaging portion engages and holds the movable contact away from the stationary contact and in open circuit position, and an actuator means cooperating with the operating member for moving said operating member fr'omnormal position to an operated position, the contact engaging portion permitting the movable'contact to'move toward and into engagement with said stationary contact and to be released therefrom and held in electrical engagement with the stationary switch member by the urging means prior to completion of movement of the operating member to operated position whereby the closed contacts are free of any connection to the operating member, thus eliminating vibration as may be transmitted by the actuator.

9. An electrical switch unit comprising a housing of insulating material having a recess therein and locating projections at the top edge thereof; a stationary contact member having one end mounted on the housing and the other end projecting into the recess; screw means threaded into the housing and cooperating with the lastnamed end to adjust the position of said stationary contact; a movable contact member mounted on the housing to project into the recess and having a portion intermediate the ends thereof cooperable with the stationary contact to close a circuit therebetween; terminals on the housing connected to said contact members; urging means urging the movable contact to closed circuit posi- 30 2,782,287

tion; a separate resilient operating member mounted on the housing and disposed on the side of the movable. contact-opposite said stationary contactand having a contact-engaging portion extending above overlying the end of the movable contact member, said resilient member having a normal position wherein the contact-engaging portion, forming the sole operating connection to the movable contact, engages and holds the movable contact away from the stationary contact and in open circuit position, a reciprocating actuator means mounted in -a tubular bearing on the housing and cooperating withzthe operating member for moving said operating member from normal position to an operated position, the contact-engaging portion permitting the movable contact to move toward and into engagement with said stationary contact and to be held in electrical engagement with the stationary switch member by the urging means prior to completion of movement of the operating member to operated position whereby the closed contacts are free of any connection with the operating member and of vibration as may be transmitted by the actuator, and a transparent cover for said recess to enclose and protect the contacts from foreign matter.

References Cited in the file of this patent UNITED STATES PATENTS Rhoades Apr. 19, 1910 Koppelmann et a1. Feb. 9, 194-3 Smith Feb. 19, 1957 

